MCQOPTIONS
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MCQOPTIONS
This section includes 568 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 451. |
The largest consumer of refractories is the __________ industry. |
| A. | cement |
| B. | metallurgical |
| C. | fertiliser |
| D. | power |
| Answer» C. fertiliser | |
| 452. |
Refractoriness under loads (RUL) is quite close to the fusion temperature (PCE) for __________ bricks. |
| A. | fireclay |
| B. | silica |
| C. | dolomite |
| D. | very low alumina |
| Answer» C. dolomite | |
| 453. |
Silliminite (Al2O3.SiO2) refractory, which is a neutral refractory, is not used in |
| A. | pottery furnace |
| B. | glass melting furnace |
| C. | crucibles |
| D. | gas retorts |
| Answer» E. | |
| 454. |
Ramming masses are used for |
| A. | obtaining monolithic working faces. |
| B. | repairing construction of various furnace parts. |
| C. | both (a) & (b). |
| D. | neither (a) nor (b). |
| Answer» D. neither (a) nor (b). | |
| 455. |
Crushing strength of a refractory |
| A. | increases with rise in service temperature. |
| B. | decreases with rise in service temperature. |
| C. | is unaffected with change in service temperature. |
| D. | decreases with increase in porosity. |
| Answer» C. is unaffected with change in service temperature. | |
| 456. |
Rotary kilns meant for calcination of limestone are lined with chrome magnesite in __________ zone. |
| A. | preheating |
| B. | cooling |
| C. | burning |
| D. | all |
| Answer» D. all | |
| 457. |
Mixing of ground refractory material and water is done in a __________ mill. |
| A. | pug |
| B. | ball |
| C. | tube |
| D. | rod |
| Answer» B. ball | |
| 458. |
'Spinel', a refractory mineral is chemically represented as |
| A. | MgAl2O4 |
| B. | MgAl2O3 |
| C. | MgSO4 |
| D. | MgAl2O3.2H2O |
| Answer» B. MgAl2O3 | |
| 459. |
Zirconia refractory |
| A. | does not react with basic slags. |
| B. | is produced from baddeleyite. |
| C. | can not be used as an insulator. |
| D. | has poor electrical conductivity at high temperature. |
| Answer» C. can not be used as an insulator. | |
| 460. |
Which form of silica has the highest specific gravity ? |
| A. | Quartz |
| B. | Cristobalite |
| C. | Tridymite |
| D. | All have the same specific gravity |
| Answer» B. Cristobalite | |
| 461. |
Carbon refractories have very high |
| A. | wetting characteristics |
| B. | refractoriness |
| C. | thermal conductivity |
| D. | both (b) and (c) |
| Answer» E. | |
| 462. |
Maximum safe working temperature for fireclay bricks is about __________ °C.$ |
| A. | 1150 |
| B. | 1300 |
| C. | 1450 |
| D. | 1550 |
| Answer» E. | |
| 463. |
Magnesite bricks have poor resistance to attack by __________ slag. |
| A. | lime |
| B. | basic |
| C. | acid |
| D. | none of these |
| Answer» D. none of these | |
| 464. |
Which is a neutral refractory ? |
| A. | Graphite |
| B. | Magnesite chrome |
| C. | Silica |
| D. | Magnesia |
| Answer» B. Magnesite chrome | |
| 465. |
Ceramic recuperators used for waste heat recovery from high temperature flue gas going out of the furnace is made of |
| A. | fireclay |
| B. | silicon carbide |
| C. | corrundum |
| D. | siliceous fireclay |
| Answer» C. corrundum | |
| 466. |
__________ is the measure of the strength of refractory under the combined effect of temperature & load. |
| A. | Porosity |
| B. | RUL |
| C. | Specific gravity |
| D. | Thermal conductivity |
| Answer» C. Specific gravity | |
| 467. |
__________ bricks are used in the burning zone of a cement rotary kiln. |
| A. | High alumina |
| B. | Fireclay |
| C. | Thoria |
| D. | Silicon carbide |
| Answer» B. Fireclay | |
| 468. |
Grog addition in fireclay during brick manufacture is done to |
| A. | reduce its shrinkage on heating. |
| B. | impart greater spalling resistance. |
| C. | enhance the strength of fired refractories. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 469. |
Which furnace consumes maximum refractory annually in an integrated steel plant ? |
| A. | Soaking pit |
| B. | Blastfurnace |
| C. | L.D. converter |
| D. | Coke ovens |
| Answer» D. Coke ovens | |
| 470. |
Semi-silica bricks compared to silica bricks have |
| A. | less fusion point. |
| B. | better spalling resistance. |
| C. | both (a) and (b). |
| D. | neither (a) not (b). |
| Answer» D. neither (a) not (b). | |
| 471. |
Fusion point of a basic refractory material is |
| A. | reduced by the addition of acid oxides. |
| B. | increased by the addition of acid oxides. |
| C. | not affected by the addition of acid oxides. |
| D. | always less than 1000°C. |
| Answer» B. increased by the addition of acid oxides. | |
| 472. |
Silica bricks have low spalling resistance below 600°C, due to its$ |
| A. | very high thermal conductivity. |
| B. | high co-efficient of expansion upto this temperature. |
| C. | high thermal diffusivity. |
| D. | low refractoriness. |
| Answer» C. high thermal diffusivity. | |
| 473. |
Which brick undergoes maximum shrinkage on drying ? |
| A. | Tar bonded dolomite bricks |
| B. | Fireclay bricks |
| C. | Magnesite bricks |
| D. | Chromite bricks |
| Answer» C. Magnesite bricks | |
| 474. |
Which is not a basic refractory ? |
| A. | Chrome magnesite |
| B. | Magnesite |
| C. | Dolomite |
| D. | Silicon carbide |
| Answer» E. | |
| 475. |
Zirconia refractories are not used in |
| A. | making sheaths for thermocouple. |
| B. | lining high temperature ceramic kilns. |
| C. | furnaces subjected to fluctuating temperature. |
| D. | high frequency induction furnaces in the form of inductors. |
| Answer» D. high frequency induction furnaces in the form of inductors. | |
| 476. |
Refractory bricks having lower porosity have |
| A. | high insulating properties |
| B. | low heat capacity |
| C. | low thermal conductivity |
| D. | greater strength |
| Answer» E. | |
| 477. |
Silica refractories are not used in |
| A. | coke oven walls. |
| B. | beehive coke ovens. |
| C. | dome and upper portion of B.F. stoves. |
| D. | open hearth furnace roof. |
| Answer» C. dome and upper portion of B.F. stoves. | |
| 478. |
Fireclay bricks is not used for lining the |
| A. | cupola. |
| B. | gas producer. |
| C. | bottom of hot metal mixer. |
| D. | roof of open hearth furnace. |
| Answer» D. roof of open hearth furnace. | |
| 479. |
Test piece for determination of RUL of a refractory is heated in a/an |
| A. | oxidising atmosphere |
| B. | reducing atmosphere |
| C. | electric furnace |
| D. | neutral atmosphere |
| Answer» D. neutral atmosphere | |
| 480. |
Maximum water percentage in refractory mix meant for hand moulding may be as high as __________ percent. |
| A. | 43526 |
| B. | 43651 |
| C. | 43806 |
| D. | 14-20 |
| Answer» E. | |
| 481. |
Ganister is a source of the |
| A. | silica |
| B. | periclase |
| C. | lime |
| D. | none of these |
| Answer» B. periclase | |
| 482. |
Spalling of silica bricks occurs due to abrupt volume changes, when it is cooled below a temperature of __________ °C.$ |
| A. | 770 |
| B. | 570 |
| C. | 270 |
| D. | 70 |
| Answer» D. 70 | |
| 483. |
Most Cermets, which normally have high thermal conductivity and high thermal shock resistance, comprises of ceramic & metallic components of __________ percent respectively. |
| A. | 80 and 20 |
| B. | 20 and 80 |
| C. | 50 and 50 |
| D. | 60 and 40 |
| Answer» B. 20 and 80 | |
| 484. |
Cold crushing strength of ordinary fireclay brick is about 950 kg/cm2 . On exposure to a temperature of about 1500°C, its crushing strength may come down to as low as __________ kg/cm2 .$ |
| A. | 450 |
| B. | 250 |
| C. | 150 |
| D. | 65 |
| Answer» E. | |
| 485. |
Outer combustion chamber of blast furnace stove is lined with __________ bricks. |
| A. | fireclay |
| B. | silica |
| C. | chrome magnesite |
| D. | zirconia |
| Answer» B. silica | |
| 486. |
Thoria |
| A. | has high fusion temperature (> 3000°C) but poor resistance to thermal shock. |
| B. | has high resistance to basic slags. |
| C. | which is expensive & radioactive, is used in crucibles for melting high purity metals. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 487. |
Which is the stable form of silica between 1470°C and the melting point 1713°C ?$ |
| A. | Cristobalite |
| B. | Tridymite |
| C. | Quartz |
| D. | None of these |
| Answer» B. Tridymite | |
| 488. |
Bottom of basic open hearth furnace are constructed of |
| A. | dead burnt magnesite ramming mass. |
| B. | porous fireclay bricks. |
| C. | semi-silica bricks. |
| D. | silicon carbide bricks. |
| Answer» B. porous fireclay bricks. | |
| 489. |
With increase in the porosity, thermal spalling resistance of fireclay brick |
| A. | increases |
| B. | decreases |
| C. | remains same |
| D. | may increase or decrease |
| Answer» B. decreases | |
| 490. |
Fusion point of an acidic refractory material is |
| A. | increased by the addition of basic oxides. |
| B. | reduced by the addition of basic oxides. |
| C. | not affected by the addition of basic oxides. |
| D. | always more than 2500°C. |
| Answer» C. not affected by the addition of basic oxides. | |
| 491. |
Maximum shrinkage in volume occurring during burning/firing of dried refractories may be as high as __________ percent. |
| A. | 10 |
| B. | 15 |
| C. | 20 |
| D. | 30 |
| Answer» E. | |
| 492. |
Grog |
| A. | contains both alumina and silica. |
| B. | iscrushed firebrick. |
| C. | is a non-plastic material. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 493. |
Fireclay bricks are not used in the |
| A. | beehive coke oven. |
| B. | by-product coke oven walls. |
| C. | combustion chamber of B.F. stoves. |
| D. | coke oven regenerators. |
| Answer» C. combustion chamber of B.F. stoves. | |
| 494. |
Sillimanite is a __________ refractory. |
| A. | basic |
| B. | neutral |
| C. | high alumina |
| D. | insulating |
| Answer» D. insulating | |
| 495. |
Refractoriness under load (RUL) of fireclay bricks (under a load of 2 kg/cm2 ) is __________ °C.$ |
| A. | 500 |
| B. | 1000 |
| C. | >1350 |
| D. | >2000 |
| Answer» D. >2000 | |
| 496. |
Refractory bricks with lower permeability is produced by using |
| A. | higher firing temperature. |
| B. | higher moulding pressure. |
| C. | finer grog size. |
| D. | all (a), (b) and (c). |
| Answer» E. | |
| 497. |
Si percentage in silica refractories used in the walls of coke oven is about |
| A. | 45 |
| B. | 60 |
| C. | 80 |
| D. | 95 |
| Answer» E. | |
| 498. |
A steel member used in the furnace construction to take the thrust of the brickwork is called |
| A. | buckstay |
| B. | breast wall |
| C. | armouring |
| D. | baffle |
| Answer» B. breast wall | |
| 499. |
Magnesite bricks are used in those parts of furnaces, which are |
| A. | subjected to temperature fluctuation. |
| B. | required to resist corrosive basic slag. |
| C. | subjected to high load. |
| D. | none of these. |
| Answer» C. subjected to high load. | |
| 500. |
Vacuum steel degassing units are lined with |
| A. | silica bricks |
| B. | low duty firebricks |
| C. | high alumina bricks |
| D. | graphite blocks |
| Answer» D. graphite blocks | |